IEEE Power & Energy Magazine - January/February 2014 - 54

The Healing Touch

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Digital Object Identifier 10.1109/MPE.2013.2285609
Date of publication: 17 December 2013

Major electric power disturbances can be triggered
by storms, heat waves, solar flares, and many other sources, but all have
their roots in the mechanical, cyber, and human vulnerabilities of existing
power grids. as shown in Figure 1, 2012 was a particularly bad year for
extreme weather in the united states. an aging grid infrastructure only exacerbates this problem by creating new concerns over energy reliability and
grid resiliency. a single storm can cost billions of u.s. dollars in terms of
direct damage to the grid, and it can cause significant power outage-related
costs, including lost productivity.
it has been argued based on historical data and computer modeling that
power grids are self-organized critical systems. these systems experience
unavoidable disturbances that result in the loss of portions of the system
or the entire system. this phenomenon has been attributed to steadily
increasing load, reduced operating budgets and lower capital investment
by power companies, and the technical limits of modern engineering.
"power delivery systems have a lot of parts, wires, transformers, and
other components all nicely tied together-which means there are a lot of
things that can go wrong," explains clark gellings of the nonprofit electric
power research institute (epri). "pieces break down, and people make
errors. a system is designed to tolerate a certain amount of disruption, but
past a certain point it's simply gone too far, and it falls apart."
epri has estimated that "across all business sectors, the u.s. economy
is losing between us$104 billion and us$164 billion a year to outages."
by minimizing or eliminating interruptions, the self-healing grid could
dramatically reduce this cost. widespread blackouts, such as the 2003 outages in the united states and italy, the 2006 outage in europe, or the massive 2012 blackouts in india, are powerful reminders of the catastrophic
consequences of power system outages.
Figure 2 shows the amount of load lost due to major blackout events in
the united states for the years 1965 through 2003. all these blackouts had
large adverse effects. For example, the great northeast blackout of 1965,
which began when a power surge in new York near the ontario border
set off a chain of failures across new York state and beyond, covered
80,000 mi2. "within four minutes, the line of darkness had plunged across
Massachusetts all the way to boston," The New York Times reported on
the day of the outage. "it was like a pattern of falling dominoes-darkness sped southward through connecticut, northward into Vermont, new
Hampshire, Maine, and canada."
the need for an automated, self-healing grid has grown in recent years
as the complexity and vulnerabilities of the interconnected grid increase. at
present, system operators "manually" perform power system recovery or
restoration following a major outage based on guidelines from a restoration
plan prepared off-line that may or may not accurately address the scenario
actually taking place. Further, such restoration work is time-consuming
and highly stressful for system operators. the complex tasks of emergency

ieee power & energy magazine

By Shanshan Liu,
Yunhe Hou,
Chen-Ching Liu,
and Robin Podmore

january/february 2014

Table of Contents for the Digital Edition of IEEE Power & Energy Magazine - January/February 2014